This invention relates to gas sterilization and in particular to such sterilization in a portable sterilizer.
Gas sterilizers are typically utilized for example in hospitals for treating articles, for example of plastic, paper, rubber or the like which cannot withstand heat sterilization. Sterilization is effected when gaseous sterilizing agent reacts with contaminating microorganisms to kill or inactivate them. The most popular sterilizing agent presently employed is ethylene oxide in admixture with an inert diluent such as dichlorodifluoromethane.
The aforementioned reaction is carried out most effectively with the aid of a reaction solvent, typically water. It is theorized that the reaction solvent forms a coating on a microorganism, and the reaction occurs in this coating at the microorganism surface. The introduction of the reaction solvent into the sterilizer is referred to in the art as humidification.
In larger permanently emplaced sterilizers, humidification is expediently accomplished by introduction of low-pressure steam. However, in small (for example, 1/2 to 3 cubic feet), portable sterilizers, it is not feasible to connect a steam line for humidification purposes. For portable sterilizers the most common method of humidification comprises pouring a measured amount of water on the sterilizer floor after loading and just prior to closing the sterilizer door and initiating ethylene oxide introduction; this method is referred to as "puddling".
The puddling method has disadvantages. Firstly, it is slow. The water must vaporize from the puddle in order to be distributed through the load and penetrate to the microorganisms. This takes time. Secondly, this method relies on the operator to remember to add the water.
A main object of this invention is the provision of a system and method whereby humidification is carried out so that a significant savings in time is achieved. Another object is to provide a system which minimizes reliance on an operator for humidification and produces a precise predictable humidity level from run to run. Still another object of one very preferred embodiment of the invention is the provision of a more effective humidification composition.
These objects and others will be evident from the following detailed description.